As temperatures start to drop, fleet managers schedule diesel fuel testing as part of their fall preventive maintenance routine. They know that cold weather can turn even high-quality diesel into a liability if it’s not properly conditioned. In essence, testing in advance ensures smooth, reliable operation all winter long.
Diesel contains paraffin wax that can solidify in low temperatures. When this happens, the fuel’s Cold Filter Plugging Point (CFPP) and Cloud Point rise, making it thick enough to clog filters and prevent engines from starting. Fall testing identifies fuels that need to be treated with cold-flow improvers or anti-gel additives.
Seasonal temperature swings also lead to condensation in fuel storage tanks. The resulting water promotes microbial growth and rust that can damage injectors and filters. Testing in the fall helps operators remove water and apply biocides before problems occur.
Also, fuel that has aged or been improperly blended may lose cetane quality (making cold starts harder) and lubricity (increasing wear on pumps and injectors). Standard analyses confirm that stored or delivered diesel meets ASTM D975 specifications for winter reliability.[1]
Stored and New Fuel Both Need Testing
Testing should include not only on-site stored fuel but also new deliveries before being put into service. Stored fuel is vulnerable to condensation, oxidation, and microbial buildup, while new deliveries can arrive off-spec or inadequately blended for cold weather.
Key Tests
The most common cold weather diesel tests target properties that determine operability and contamination risk. These tests include:
- Cloud Point, CFPP, and Pour Point: These tests predict waxing and flow issues at low temperatures.
- Water and Sediment (ASTM D2709 or D6304): These tests identify moisture that can freeze or foster microbial growth.
- Microbial Contamination (ASTM D6469): This test detects bacteria or fungi at the fuel-water interface.
- Distillation and Flash Point: These tests confirm correct volatility and blending ratios for winter diesel or kerosene.
Additives
Cold-weather diesel fuels are usually treated with additives at the refinery or terminal. This blend of performance additives may include:
- Cold-flow improvers
- Pour-point depressants
- De-icers
- Cetane enhancers
- Corrosion inhibitors, etc.
However, because these additives can degrade, settle, or become less effective due to oxidation or contamination during storage, levels need to be verified.
Failing to test diesel before winter can lead to gelling, ice blockage, sludge formation, and engine shutdowns—causing lost productivity, unfilled commitments, and expensive repairs, A modest investment in cold weather testing and treatment prevents all of this and ensures engines start when reliability matters most.
To schedule Diesel Fuel Testing or for more information on working with Eurofins TestOil for fuel analysis, oil analysis or training visit https://testoil.com/company/contact-us/; call 216-251-2510; or email sales@et.eurofinsus.com.
With more than 30 years of experience in the oil analysis industry, Eurofins TestOil focuses exclusively on assisting industrial facilities with reducing maintenance costs and avoiding unexpected downtime through oil and fuel analysis program implementation. As industry experts in diagnosing oil-related issues in equipment such as turbines, hydraulics, gearboxes, pumps, compressors and diesel generators, Eurofins TestOil provides customers with same-day turnaround on routine oil analysis testing.
About Eurofins – the global leader in bio-analysis
Eurofins is Testing for Life. Eurofins is the global leader in food, environment, pharmaceutical and cosmetic product testing, and in discovery pharmacology, forensics, advanced material sciences and agroscience Contract Research services. Eurofins is also a market leader in certain testing and laboratory services for genomics, and in the support of clinical studies, as well as in BioPharma Contract Development and Manufacturing. The Group also has a rapidly developing presence in highly specialised and molecular clinical diagnostic testing and in-vitro diagnostic products.
With over 61,000 staff across a network of 940 laboratories in 59 countries, Eurofins’ companies offer a portfolio of over 200,000 analytical methods. Eurofins Shares are listed on Euronext Paris Stock Exchange.
[1] ASTM D975 is the standard specification for diesel fuel oils. It defines performance requirements, properties, and test methods to ensure fuel quality, consistency, and compatibility with diesel engines.
